RESUMO
Advanced glycation end products (AGE) are elevated in diabetes mellitus (DM) and predict the development of atherosclerosis. AGE-albumin induces oxidative stress, which is linked to a reduction in ABCA-1 and cholesterol efflux. We characterized the glycation level of human serum albumin (HSA) isolated from poorly controlled DM2 (n = 11) patients compared with that of control (C, n = 12) individuals and determined the mechanism by which DM2-HSA can interfere in macrophage lipid accumulation. The HSA glycation level was analyzed by MALDI/MS. Macrophages were treated for 18 h with C- or DM2-HSA to measure the (14) C-cholesterol efflux, the intracellular lipid accumulation and the cellular ABCA-1 protein content. Agilent arrays (44000 probes) were used to analyze gene expression, and the differentially expressed genes were validated by real-time RT-PCR. An increased mean mass was observed in DM2-HSA compared with C-HSA, reflecting the condensation of at least 5 units of glucose. The cholesterol efflux mediated by apo AI, HDL3 , and HDL2 was impaired in DM2-HSA-treated cells, which was related to greater intracellular lipid accumulation. DM2-HSA decreased Abcg1 mRNA expression by 26%. Abca1 mRNA was unchanged, although the final ABCA-1 protein content decreased. Compared with C-HAS-treated cells, NADPH oxidase 4 mRNA expression increased in cells after DM2-HSA treatment. Stearoyl-Coenzyme A desaturase 1, janus kinase 2, and low density lipoprotein receptor mRNAs were reduced by DM2-HSA. The level of glycation that occurs in vivo in DM2-HSA-treated cells selectively alters macrophage gene expression, impairing cholesterol efflux and eliciting intracellular lipid accumulation, which contribute to atherogenesis, in individuals with DM2.
Assuntos
Transportador 1 de Cassete de Ligação de ATP/metabolismo , Colesterol/metabolismo , Diabetes Mellitus Tipo 2/genética , Macrófagos/metabolismo , Albumina Sérica/metabolismo , Adulto , Animais , Aterosclerose/genética , Aterosclerose/metabolismo , Transporte Biológico/genética , Transporte Biológico/fisiologia , Colesterol/genética , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Expressão Gênica/fisiologia , Produtos Finais de Glicação Avançada , Humanos , Masculino , Camundongos , Estresse Oxidativo/genética , Albumina Sérica/genética , Albumina Sérica GlicadaRESUMO
The behaviour of some N,N'-disubstituted hexahydropyrimidines, a class of naturally occurring compounds of biological and biomedical interest, has been studied in both electron ionization (EI) and electrospray ionization (ESI) modes coupled with collisional experiments (ESI-MSn). In both techniques, the [M-H]+ ions are highly abundant, even if their formation is generated by two different mechanisms, i.e. H. loss from the M+. species in the case of EI and hydride (H-) abstraction from the molecules in the case of ESI. Furthermore, due to the low, step-by-step internal energy deposition typical of collisional experiments performed in an ion trap mass spectrometer, different fragment ions were observed in EI and ESI-MSn collisions. In both cases, the ions can be related to the original structure and allow us to identify the positions in which the different substituents are present.
Assuntos
Elétrons , Pirimidinas/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Produtos Biológicos/química , Íons/química , Pró-Fármacos/químicaRESUMO
It is well known that proteins and peptides play an important role in the flavour of roasted coffee, but little is reported in the literature about their characterization. In view of the potential of matrix-assisted laser desorption/ionization mass spectrometry in the analysis of proteins in complex mixtures, two varieties of coffee green beans, Arabicas and Robustas, were analyzed by this technique, in order to obtain fingerprints of their native proteins. Differences were observed between Arabicas and Robustas green beans, and cluster analysis allows differentiation of samples of the same variety from different plantations.